In recent years, various light source modules using a semiconductor light emitting device such as an LED (Light Emitting Diode) as a light source are being proposed. Such light source modules are being used in, for example, a vehicle lamp for irradiating light emitted from a light source as illumination light. A light source module includes a circuit board placed on a mounting base of a light source holding member and having a surface on which a semiconductor light emitting device is mounted, and a power feeding attachment coupled to a power supply circuit to feeding power to the semiconductor light emitting device. A pair of connecting terminals provided in the power feeding attachment is connected to a pair of power feeding pieces formed on the circuit board respectively (see, e.g., Patent Document 1).
For the semiconductor light emitting device to effectively emit light as a light source of a vehicle lamp, it is necessary to prevent luminance from lowering due to heat. Accordingly, a back surface of the circuit board is brought into firm contact with the mounting base of the light source holding member, so that the heat emitted from the semiconductor light emitting device is released to the light source holding member.